1. Technical Field
The present invention relates to an X-ray diagnostic apparatus, and it particularly relates to a technique in which a photographing region is moved in response to injection of image forming agent or contrast medium.
2. Background Art
In recent years, there has been rapidly developed an X-ray diagnostic apparatus which combines and consists of an image intensifier that converts an X-ray image to an optical image, and other image processing technology where the optical image is photographed to be converted to a video signal and then the video signal is digital-image-processed so as to be displayed on a display monitor.
When such an X-ray diagnostic apparatus is utilized, an operator such as a doctor or an X-ray technician determines a position thereof, viewing a television monitor that displays a fluoroscopic image, so that a desired photographing can be performed.
However, in X-ray photography in which the image forming agent is injected into blood vessels, it is difficult to position an examined biological body and take a proper timing for photographing the biological body. In order to overcome such a problem, it is required for the operator to have sufficient experience and trained intuition.
Particularly in photography of lower limb using the image forming agent, there are many photographing spots, and flow rates of blood differs at a major portion and a peripheral portion of the biological body. Therefore, in the conventional practice, the operator moves a supporting member (bed portion) to photograph a desired portion of the biological body in a manner that the operator observes the motion of the image forming agent viewing the television monitor and he predicts a next motion of the image forming agent based on the observation.
As mentioned above, a burden is heavy to the operator in a photographing technique where the supporting member is manually moved repeatedly viewing the fluoroscopic image. Moreover, there are caused many unsuccessful photographic results, for example, where the image forming agent is not photographed in the photographing image region. Thus, it is difficult to have desired photographing images in the conventional practice.